Optical fiber connectors are often subjected to severe external stresses which can damage the connectors and cause misalignment or separation of the optical fibers that are mated by the connectors. For example, in applications where connectors are subject to frequent connection and disconnection, stresses are often placed on an optical fiber cable which can loosen or otherwise damage the attachment of that cable to the connector. This damage often interferes with the efficient transmission of a signal between the optical fibers of the mated connectors.
The incorporation of a strain relief structure into an optical fiber connector so as to help isolate the delicate optical fibers from external stresses and to help maintain the integrity of the optical fiber connection is well known. See, for example, U.S. Pat. Nos. 4,787,706; 4,826,277; 4,588,256; 4,729,619; 4,909,583; and 5,202,942.
None of the fiber optic strain relief structures developed to date are completely satisfactory. In particular, many of these prior art strain relief structures require a significant amount of excess material so as to provide the requisite strength and stability. This often results in bulky and expensive designs that are difficult to assemble.
For example, U.S. Pat. No. 5,202,942, issued to Collins et al., discloses a cable termination member having a strain relief feature for isolating the optical fiber members from external stresses in a terminated optical fiber cable. The cable termination member is adapted to terminate an optical fiber cable which includes at least one optical fiber member, a load bearing member around the fiber, and an outer jacket surrounding the load bearing member. This design also includes a first outer crimp member that is adapted to receive an end of the optical fiber cable and a second outer crimp member that is crimped to the first outer crimp member with an exposed portion of the load bearing member crimped therebetween. An inner crimp member is positioned in the cable between the optical fiber member and the load bearing member and within the first and second outer crimps. This structure is adapted to secure the cable jacket between the first outer crimp member and the inner crimp. The inner crimp comprises a ring or eyelet that firmly secures both the load bearing member and the jacket of the cable to the termination member to provide improved strain relief for protecting optical fiber members disposed within the cable against external stresses. An annular outwardly extending flange is provided on the body of the cable termination member. This flange projects outwardly so as to engage a corresponding slot defined in a connector housing. When the cable termination member is assembled to a connector housing, the flange protrudes through the housing wall so as to provide added tensile strength to the termination member.